Oil leak from filler cap

[PaulW21781]

My bike seems to have developed a bit of an oil leak from the filler cap on the head, its been doing it for about 1k miles now, only a whispered really but still annoying.

I've tried nipping it up a bit but to no success and also changing the O-ring, and even after its 6k service its still doing it.

This common? Any tips on sorting it? Or is it just a case of shit design / crappy plastic filler cap??

Cheers!

 

[RADZIOL]

had the same prob.... bought new metal cap from bmw and all good now

 

[VAL. H.]

My bike seems to have developed a bit of an oil leak from the filler cap on the head, its been doing it for about 1k miles now, only a whispered really but still annoying.

I've tried nipping it up a bit but to no success and also changing the O-ring, and even after its 6k service its still doing it.

This common? Any tips on sorting it? Or is it just a case of shit design / crappy plastic filler cap??

Cheers!

I was going to sugest you change the 'O' ring for a new one. seeing you have already done this, I wonder if it's the same size as the original (ring diamiter and rubber diamiter, not too hard either).

I'm now thinking you need to check the engine breather pipes, because if the replacement 'O' ring is correct, then you seem to have a higher than normal pressure build up in there.

Could be just a build-up of grime on the end of the breather tube.


Val.

 

[Boxerboy55]

I never had leaks with my original cap, but have also changed to an alloy cap with torx hole that will keep any saboteurs at bay a bit longer. Never leaks.

If your O ring is the right size and a good fit, I think it would take a heck of a lot of crankcase pressure to blow past it.
I'd expect some other seal to pass before the filler cap.

I'd take a very close look at the finish of your existing cap where the O ring sits. It's more likely to be damaged (nicked, scratched, chipped) than the alloy rocker cover seat.

 

[R17GSR]

Plastic threads stretch easily and can also split through at the bottom of the thread, looking ok until it's tensioned .
Ride free
Gary